By the time your former partner is married, there is a good likelihood that the new spouse has been in their life – and that of the child’s – for some time. They have gotten to know each other.
However, many parents still find themselves in conflict about what care the new spouse may provide, and even if the new spouse should attend extra-curricular activities or otherwise be involved as a caring stepparent.
When these issues remain, there is often some underlying unresolved issues contributing to the conflict. Those issues may be about how the former partner and new spouse’s relationship came about; it may be about moving in together before one has fully adjusted to the notion of the separation; or there may be concerns about the new spouse forming a more favourable relationship with one’s own child. Although I see it far less often, those issues may also be about the actual ability of the new spouse to provide appropriate care for whatever reason.
Looking at these matters from the child’s point of view, these issues may cause the child to feel in a loyalty bind. Not uncommonly, the child experiences a reasonable relationship with the new stepparent, however owing to the feelings of their other parent, may feel unsafe talking about the new relationship in a positive manner.
Indeed, some kids, owing to the feelings of a parent, will concoct stories to appease that parent’s bad feelings towards the stepparent, even though they don’t really hold the feelings they expressed. This is to facilitate peace with their parent, not realizing that inadvertently it can fuel more discontent and drive conflict.
Again, from the child’s point of view, when cared for by more adults, their experience is one of feeling worthy, of value.
You don’t have to love the former partner’s new spouse for your child to enjoy this relationship. In fact, when supported by you, the child’s appreciation of that relationship is now a positive reflection on yourself. These things don’t have to undermine a parent’s relationship with their child. Done with poise and compassion, supporting all your child’s relationships becomes an admirable quality of the parent.
As for the initial question then… up to you.